1. Field of Invention
The present invention relates generally to regulating access rates in a computer system, and specifically to regulating file access rates of software processes according to file type.
2. Background of Invention
Multitasking operating systems such as UNIX® and Microsoft WINDOWS NT®are widely utilized in commercial computing systems. Among their many commercial uses, these operating systems are commonly deployed on Internet and other network server computers. With the popularity and success of the Internet, server computer operating systems are currently of great commercial importance.
One function of a multitasking operating system is to allocate system resources to the multiple software processes that simultaneously execute under the control of the operating system. Control over the allocation of system resources by an operating system is commercially useful for a number of reasons. Multitasking operating system are commonly used on Internet web servers by Internet Service Providers (ISP's). Where an ISP provides host services to multiple customers on a single physical computer, it is desirable to allot to each virtual host a specific amount of computer resources appropriate to the needs of the customer, and preferably based upon the amount paid for the services.
For example, suppose two customers purchase host services from an ISP. The first customer is a large corporation providing financial services to thousands of clients internationally. The financial services host requires fast file access, as well as prompt response time to all client requests. Of course, the first customer is willing to compensate the ISP appropriately for providing such a level of host services. The second customer is a sole proprietorship that sells floral arrangements locally. The second customer has a very limited budget, but only requires minimal computer resources. Clearly, it is desirable for the ISP to allocate different percentages of the system resources to the two separate virtual hosts provided by the ISP for the two separate customers.
In the example above, the ISP may wish to provide the financial services host with the ability to access files at the rate of 1,000 bytes per second, but to allow the florist to access files at the rate of only 150 bytes per second. These different access rates would be based upon the different needs of the two customers, and the corresponding different compensation schemes of each. As multitasking operating systems operate today, it would be impossible for the ISP to regulate the file access rates of the different customers. Each process associated with either virtual host simply accesses the file system at the same unregulated rate, and thus it is impossible for the ISP to guarantee or restrict access rates based upon customer need and corresponding financial arrangement. What is needed is a method that facilitates the regulation of the rate at which individual processes access the file system of a multitasking operating system.
Many commercially popular operating systems such as UNIX® and Microsoft WINDOWS NT® treat communication channels as files. In such an operating system, when a process instructs the operating system to create a communication channel, the operating system returns a file descriptor. The communication channel is subsequently accessed via the file descriptor, in a similar manner as a file stored on media.
Communication channels and files stored on media are inherently different, despite the fact that both are accessed via file descriptors. It is often desirable to for an ISP to allow a single process to access files stored on media at one rate, and to access communication channels at another. For example, a customer of the ISP may need to receive and respond to client requests very quickly, but need only an average access time for files stored on the system storage device(s). Such a customer would require (and be willing to pay for) a fast communication channel access rate, but only need (and be willing to pay for) a slower access rate to files stored on media.
Multitasking operating systems today are not capable of regulating the file access rates of different processes generally, much less facilitating different access rates for specific processes based on file type. Currently, each process accesses both files stored on media and communication channels at unregulated rates, not controlled by the operating system. Thus, it is impossible for the ISP to provide customers with different access rates for files stored on media and for communication channels, based upon customer need and corresponding financial arrangement. What is further needed is a method that not only facilitates the regulation of the rate at which individual processes access the file system of a multitasking operating system, but which also allows processes to be regulated to different access rates for different file types.
It is further desirable to not only be able to set separate access rates for communication channels and files stored on media, but to be able set separate access rates for file types generally. Under some operating systems, entities other than communication channels and files stored on media are treated as files, and hence need separate access rates. For example, under the UNIX® operating system, hardware devices are treated as files. For the same reasons that it is desirable to set separate access rates for communication channels and files stored on media, it is further desirable to be able to set a separate access rate for any type of file. Accordingly, what is needed is a method to set separate access rates for individual processes according to file type.